Part of their argument was that temporary workers at the company's Tracy processing facilities are kept in that status for years without benefits or job security.

Taylor Farms CEO Bruce Taylor said Thursday by email the bill's passage would not change anything at the plants.

"Taylor Farms Tracy operations treat our 400 temporary workers with the same workplace safety, dignity and respect as our 500 full time workers" he wrote. "Over half of the promotions awarded in Tracy the last two years have gone to our temporary workers."

In a statement, Teamsters President Jim Hoffa said the loophole which allowed employers to shift responsibility to temp agencies cheated workers.

"We are one step closer to preventing companies from engaging in a 21st century scam by claiming the men and women who do their work are not really employees but 'temporary' workers for labor contractors or agencies," he said. "This corporate shell game allows corporations to deny responsibility for basic worker rights like pay, benefits, and working conditions."

AB 1897 must go back to the Assembly to approve changes in the Senate before it goes to the governor's desk.

It still faces substantial opposition from business groups, including the California Chamber of Commerce, which has given it a spot on its "job killer" list.

In an op-ed published on the Fox & Hounds blog, California Retailers Association CEO Bill Dombrowski called the bill a "gross overreach."

He said the bill would shift accountability "by unfairly holding the majority of California employers liable for the wage and hour violations of another that they could not control or prevent."